The central theme of this program is the study of response of cells to injury with particular emphasis on the processes occurring at the subcellular and molecular levels. Several different aspects of the cell response to injury relevant to the problems involved in trauma and repair are being investigated. Among these are the healing processes as they occur in arteries and connective tissues, the formation and structure of connective tissue proteins including collagen, elastin and the glycoproteins, which provide the tensile strength for the tissues; effects of age, genetic, and metabolic factors, on fibroblast proliferation; factors involved in the production of myocardial cell injury in trauma; effects of drugs and anesthetic agents on the liver, and the role of antibodies to tissue constituents in relation to trauma and to transplantation. A major objective of the program project is to provide a technical and ideologic base for the application of the modern concepts of cellular and molecular biology to investigation of these pathologic problems. BIBLIOGRAPHIC REFERENCES: Eriksen, N., Ericsson, L.H., Pearsall, N.N., Lagunoff, D., and Benditt, E.P. Mouse amyloid protein AA: Homology with nonimmunoglobulin protein of human and monkey amyloid substance (amino-acid sequence/molecular weight/spleen/liver). Proc. Nat. Acad. Sci. USA 73:964, 1976. Schwartz, S.M. and Benditt, E.P. Clustering of replicating cells in aortic endothelium. Proc. Nat. Acad. Sci. USA 73:651, 1976.